Major depressive disorder is a common, recurrent, and impairing condition that predicts future suicide attempts, interpersonal problems, unemployment, substance abuse, and delinquency. Cognitive models of depression suggest that biased processing of dysphoric information contributes to the maintenance of the disorder. Despite empirical support for cognitive theories of depression, all previous research has been correlational. This is a major limitation. Without experimentally manipulating biased attention, it is impossible to rule out that attentional bias is simply a consequence of MDD and has no causal role in the maintenance of the disorder. Demonstrating that biased attention has a causal role would provide important insight into the processes that maintain MDD. We present preliminary data that attention training can significantly reduce depressive symptoms among adults. Building on this preliminary work, we are now proposing to investigate whether changing negatively biased attention reduces depressive symptoms among individuals diagnosed with Major Depressive Disorder. Aim 1 is to determine whether modifying selective attention for dysphoric stimuli reduces depression symptoms to a greater extent than an attention training control among adults diagnosed with MDD. Aim 2 is to investigate whether attention training alters the function of neural circuitry involved in attentional processing of emotion stimuli. Aim 3 is to test whether attention training improves other cognitive biases implicated in depression maintenance, such as sustained processing of dysphoric stimuli and enhanced recall of emotion stimuli. This would be the first study to determine whether negatively biased attention has a causal role in the maintenance of depression symptoms among adults with MDD. It would also identify neural and behavioral changes that occur following attention training. Such discoveries could spur treatment development, as our project would point to specific mechanisms across behavioral (i.e., negative attention bias) and neural (e.g., improved PFC function) levels that maintain MDD and could be specifically targeted by psychological or pharmacological interventions. Thus, the proposed study should advance our knowledge of the maintenance processes for MDD and provide specific direction for the design of treatment programs for this serious psychiatric problem. PUBLIC HEALTH RELEVANCE: The overarching goal of this project is to determine whether altering biased attention for dysphoric information leads to symptom improvement among adults diagnosed with Major Depressive Disorder (MDD). Determining whether negatively biased attention has a causal role in the maintenance of MDD would advance our knowledge of the maintenance processes for MDD and provide specific direction for the design of treatment programs for this serious psychiatric problem.